Diaphragm controlled operating unit



May 29, 1945. R. AvlGDOR DIAPHRAGM CONTROLLED OPERATING {JNIT FIG'. "2

Patented May 29, 1945 Rifat Avigdor, Toronto, Ontario, CanadaApplication June 10, 1942, Serial No. 446,545

Canada March 14, 1942 s claims. '(cl. 137-157) This invention relatestoa heat compensating, diaphragm controlled, operating unit for devicesoperated by fluid pressure.l

Up to the present time many devices'operated by fluid pressure have beenproduced for use in various fields. A particular problem which isconfronted in the manufacture of such devices,

and which is manifest particularly in the. case of instruments, is toprovide an instrument which will record with a reasonable degree ofaccuracy under all conditions. One serious difficulty is presented byconstant changes in temperature con- Y ditions which cause expansionand/or contraction of parts of the device. In one particular example,airplane instruments, for instance, temperatures from plus 80 FI tominus 60 F. may be encountered in a short space of time, with the resultthat due to expansion and/or contraction of parts of the instrument,inaccurate read,- ings result.

A number of attempts have been made to reduce inaccuracies caused byexpansion and/or contraction of parts due to temperature change. In somecases in instrument manufacture, bimetallic members have been employedbetween the instrument mechanism and the diaphragm operating element forreducing the eiects mentioned. Bimetallic helical springs have also beenused connecting with the pointer operating shaft of the instrument.However, while various methods of this character have reduced suchinaccuracies in some degree, the problem still re#- mains as a seriousone. l

I have found that inaccuracies due to expansion and/or contraction ofparts caused by change in temperature conditions encountered, can bereduced to a very fine degree at least and in many cases eliminated. Itis, therefore, an object of the present invention to produce` means forreducing'to a iine degree, or eliminating, inaccuracies in uid operateddevices caused by'expansion and/or contraction of metals due totemperature changes.

A further object of the invention is to provide an extremely simplestructure employing a minimun number of parts for accomplishing thisresul A still further object of the invention is to provide a means ofthis character which will 'employ no more parts than are necessary foran instrument of this character and without incor-` porating extra partsfor heat compensation.

vWith these and other objects. in view, the invention generallycomprises a diaphragm controlled loperating unit comprising aplurallty'of operatively connected elements, at least one of which is adiaphragm, the diaphragm being so formedl as to expand'and/or contractto its greatest degree substantially at right angles to its normaloperating plane in response to temperature conditions, at least one ofsaidelements being expandible and/or contractible to its greatestdegree, in a predetermined direction, in response to temperatureconditions, whereby expansion and/or contraction of said elementscontrols the effect on said device when connected with said diaphragm ofdisplacement of the diaphragm and said elements due to temperatureconditions.

The structure of the unit may be varied to suit requirements and theparts may be varied in thickness and in material to produce acooperative combination which will achieve predetermined results tocontrol, oiset or neutralize the eifects caused by vexpansion and/orcontraction of the parts. Under the present invention,

it is possible without the addition of extra heat l compensating devicesto so choose and arrange the parts that a cooperation between parts of adiaphragm, a diaphragm and its casing, a diaphragm and connecting partsbetween the casing and the mechanism operated by the diaphragm, etc., tocause the device to react in a predeter-` mined manner to temperatureconditions. This may be done in many cases when using similar materialsand in other cases by the use of dilervent materials having a differentrate of expansion and/or contraction.

The invention will be clearly understood by reference to the followingdetailed specification taken in conjunction with the accompanyingdrawings.

In the drawings-"- I Fig. 1 is a transverse section showing a unit'according to the vpresent invention illustrating said unit incross-section and in relation to other parts of the construction withwhich it is associated.

Fig. 2 is a topq plan view of the unit ill in Fig. 1. i.

Fig. 3 is a bottom plan Viewv of said unit.`

trated Fig. 4 is a transverse sectio'n taken throughl `1 to 3,Aindicates a diaphragm'controlled operating unit for devices operated byuid pressure which in the form illustrated includes two plateiikemembers I0 and IIso formed that their 'peripheraledges I2 and I3 and/orportions thereof adjacent the peripheraledges may clamp therebetween adiaphragm VB. The plate-like members otherwise are spaced apart from oneanother so as to form on each side of the diaphragm the chambers I4 andI5. The plate-like members IIl! andV II are held in airtight engagementwith the vperipheral edges of the diaphragm -by means of a ring-likemember I6 which is forced onto their peripheral edges under pressure soas nally to which theV diaphragm may be operatively connected to partsof an instrument or the like which .it is designed to operate. Thismember ispreferably formed with the upper and lower .integral clampingelements I9 and 20 which overlap the inner/peripheral edge ZI of thediaphragm and are forced thereover'into` an airtight engagementtherewith. Thus, by employing vsuch a form of connection between theplates II and the diaphragm and the connecting member I6 to connect theplate-like members I0 andl II at their peripheries, clamp the diaphragmB, a varied and wide choice,of material may be made with respect t0 thematerial of the diaphragm and the material of the enclosing casing.Moreover, substantial variations may be made with respect to the sizeandthickness of Lthese parts.

In the form of construction 'at present referred pansion ofthe diaphragmB, the eiects of the expansion of the latter on the operating mchanismconnected with the diaphragm through thev post I8 may be directlycontrol1e,d.` In` other Words, since the plate-like-members It and IIfirmly grip the peripheral edge of the diaphragm B, radial expansion ofsuch members i@ and II at a given rate 4will oiset the expansion ofdiaphragm B by effecting a linear stretching or linear counter-expansionof such diaphragm to any chosen degree. Accordingly, the movement of thepost I8 in the direction of its axis, to operate'the mechanism withwhich it is operatively connected, may be controlled to impart, to themechanism, that degree of movement which is desired and either excludeor directly control any movement thereof caused by expansion and/orcontraction of the diaphragm due to temperature conditions.

b. Controlof the movement of the post i8 caused by the effects ofexpansion and/or contraction of the diaphragm B by temperatureconditions may beeiected in the manner described or in conjunction withthe supporting structure such as the posts 22 .or may be controlleddirectly between the supporting structure such as the posts 2'2 and thediaphragm. vIn this connection, by so choosing the supporting structuresuch that it `wi-ll expand and/or contract as a result of temperatureconditions to itsgreatest degree in 'al l -given direction, the resultof such expansion and/ or contraction when co-related to the expansionand/or contraction of the diaphragm B may be employed to control theeffects of such abnor- I mal expansion and/or contraction of thediaphragm on the mechanism operated thereby. For

' instance, by directing the mass of the material of to, the plate-likemember .lis designed to carryv a plurality of posts 22, being formed forinstance,

with suitab1e bosses z3 and apertures 24 through' which the posts may besecured. These posts are designed to support, as illustrated, amechanism formed with the oriiice lla provided with the mounting memberI Ib, it is preferred to project a portion of the latter withinthisorice and force the posts 22 so that they will expand and/orcontract axially to their greatest degree at a given rate, andco-relatin'g this expansion and/or contraction of the diaphragm B, theaxialexpansion .of the posts 22 is immediately co-related to that axial'movement of the post I8 caused by eXpansion and/or contraction of thediaphragm B. Therefore, the effects of such abnormal movement of thepost I8 may be directly controlled in it into 'air sealing engagementwith the inner periphery of this plate-like member surrounding suchorice.

By so choosing the materialsl and/or size and construction for thediaphragm B, plate-like members I0 and I-l ,1 and/or the posts 22, I amable` relation to the results desired from the mechanism operatedthereby.

The control of expansion and/or contraction of the diaphragm as abovereferred to may be carried-out by a choice of materials having diierentcoeiiicients of expansion or may be controlled by variation of the massof material in question.

Thus, the diaphragm yand the casing or plateto control the effect on thedevice, or displacef lment of the diaphragm and elements of thel con`struction due to temperature conditions so'that in the case of aninstrument, for instance, no vinaccuracies in the reading will resultdue to any displacement of the parts by temperature causes or throughwhich ,a given' displacement 'may be provided for where this `might bedesirable.

In-the form vof construction being dealt with,

the diaphragm B is of such character that it willI expand and/orcontract as a result of -tempera' f' 1 .ture conditions in 'a' planesubstantially at right` 'Y angles to its normal operating plane.

like .members I0 and II are of' such area and 'I'he platelike members I0 and II may be chosenof the L same material and of the same or similarthickness or of the same material of different thicknesses.` On theother hand, vthese .parts may be cho'sen of materials which aredilerentfrom one another and of the same or similar thickness or ofdiierent thicknesses. In this waytherefore, a minute control may beobtained ofthe effect of the movement of the diaphragm due to tempera- Ature conditions. Moreover, such control, it will be thickness 'that theywill expand an'd/or contract,

as a result of temperature conditions, radially of y YYtheir centers...Thus, by controlling the rate of expansion of the plate-like members`III and Il and co-relating such expansion tothat of the exclear, may beeffected with or without rthe use of the supporting posts 22 or othermounting structure or may be caused as a combination between thediaphragm andV the supporting structure contraction of a diaphragmelement as a result alone. o v

The control of the .effects of expansion and/or of temperatureconditions may be achieved following the plinciples of the presentlinventionin The application different types of structures. of theprinciple ofthe presentinvention to capsule type diaphragm units andmultiple diaphragm unitsy is illustratedin Figs. 4 and 5. Dealing firstwith Fig. 4 wherein a capsule type diaphragm unit is disclosed, thediaphragm elements 25 and 26 may be connected together, and preferablyare, by means of a ring-like member 2i forced into Vengagementtherewithand may also be provided with a stiffening plate 28 and a similar plate29, both forced into engagement with the elements 25 and 26respectively. The diaphragm element 25 may be formed of Lone materialand the element 25 of another, each having a. coeicient of expansiondifferent from the otherD and co-related in such a manner, that theeffects of expansion land/or contraction of these diaphragm elements dueto heat conditions, may control the resulting effect on the mechanism ofthe instrument connected through the post 30. choosing theelements 25and 26 so that one may be thicker than the other and not necessarily /ofa different material, the eiects of expansion and/or contraction asabove referred to may be controlled. l

By employing the'ring-like member 27E as a means of securing thediaphragm elements together and, in the case where these elements, areof a dii'erent material, any electrolytic action l which might be set upbetween the elements,

andl lthus render the combination impractical for use in some iields,may be eliminated by interposing between the clamped surfaces of theelements a suitable dielectric. Consequently, it will be readilyappreciated that the invention has a wide application and is operableunder varied conditions.

lThe far reaching effect ofthe invention may be further illustrated byreference to Fig. showing a multiple capsule type diaphragm unit. Thisstructure includes the diaphragm elements 3i, 32, 33 and 36. that byconstructing the unit in suchV a way as to vary and co-relate thematerials ofV these four sule and clamp therebetween the circumferentialflange ofthe capsule, the plate-like members ner. Alternatively, byco-relating the expansion vthe supporting structure between the unit andOn the other hand,4 by

It will be readily appreciated being secured together by means of aring-like` f member 35a, forced into pressure engagement therewith andin effect forming an airtight seal is formed with a projection 38 whichis a continuation of a plate or the like enclosing thebottomelement ofthe capsule andA corresponding 1 to plate 29 as shown in Fig. 4. Throughthis con-* struction, the full effects of .the diaphragm unit or capsuleare obtained, whereas in addition the f' benets of a casing 'such asdescribedv in Figs.

. 1 tov 3 are also obtained.

the mechanism operated thereby, the abnormal effects of expansion and/orcontraction of the diaphragm by temperature causes is controlled in asimple manner. .As a result, therefore, it will be clear that by vscchoosing and constructing normal operating parts of such a mechanism soas to co-relate the expansion and/or contraction of such parts invquestion to the eirpansion and/or contraction of a, diaphragm elementcaused `by temperature conditions, the resulting eect of the latter maybe minutely controlled and such control may be a neutralizing of theeffects so caused or the use of such effects in some degree where thisis desirable.

.While, through the use of the principle outlined in the foregoingspecification, it is possible to control the effect of expansion and/orcontraction of'the diaphragm due to temperature causes, it will, ofcourse, be apparent that the invention will compensate for minutevariations in the physical characteristics of the material. Itis a wellestablished and obvious fact that the value of Youngs.'modulus ofelasticitsl varies with the state or condition of the material inrelationto temperature and other causes.,

The invention, therefore, lmust compensate for minute variations in thelphysical characteristics of the material used, effected through ltem-.perature or other causes. 1

mined properties of ,thermal expansibility and contractibility wherebyits maximum expansion and contraction is in a direction substantially at'right angles to the principal plane of the diaphragm, means fortransmitting movement from the diaphragm to said device, and thermalresponsive supporting means for said device in spaced position aroundsaid movement transmitting means and operatively connected to saiddiaphragm and having properties of thermal expansibility andcontractibility predeterminedly correlated to those of said diaphragmsol as to "Ihus, by providing a combination such that expansion and/orcontraction of the diaphragm due to temperature conditions-iscounteracted or controlled by a linear stretching ofthe diaphragm in adesired degree, ,depending upon the extent of control desired, thepresent invention meets this problem in a very simple mancontrol theeffective extent of transmitted movelment from vsaid diaphragm to saiddevice due to temperature changes, said supporting means havingacoefiicient of expansion different from that of said diaphragm.

2. A heat compensating, diaphragm controlled operating unit for a uidpressure operated device, ,comprising a diaphragm having predetervminedproperties of thermal expansibility'- and contractibility whereby itsmaximum expansion and, contraction isl in a. direction substantially at'right angles to the principal plane' of the dlaphragm, means fortransmitting movement from the diaphragm to said device; and thermaliesponsive` supporting means for said device-in spaced position aroundsaid movement transmit-4 ting means and operatively connectedto saiddiaphragm and having propertiesof thermal expanoperating unit for aiiuid pressure operated de. vice, lcomprising a diaphragm havingpredeter-` mined properties of thermal expansibility and contractibilitywhereby its maximum expansion and contraction is in a, directionsubstantially at right angles to the principal plane of the diag,phragm, means for transmitting movement from the diaphragm to saiddevice, and a diaphragm casing substantially ,encompassing saiddiaphragm and being in peripheral clamping engagement therewith andhaving properties of thermal expansibilityc and contractibilitypredeterminedly correlated to those of said diaphragm as to control theeffective. extent of transmitted movement from said diaphragm to saiddevice due to tem-v perature changes, said diaphragm casing having acoefficient of expansion different from that of said diaphragm and beingthermally expandible and contractible in a predetermined direction dif-K ferent from that of said diaphragm.

4. A heat lcompensating, diaphragm controlled operating unit for a iiuidpressure operated vdevice, comprising a diaphragm having `predeterminedproperties of thermal expansibility and contractibility wherebyits'maximum expansion and contraction is in a direction substantially atright angles to the prinipal plane ofv the dia--` phragm, means fortransmitting movement from the diaphragm to said device, a diaphragmcasing substantially encompassing said diaphragm and being in peripheralclamping engagement therewith, and a super-structure on said casing andinterconnecting thelatter and saidY device, said Vsuper-structure havingproperties of thermal expansibility and contractibility predeterminedlycorrelated to those of said diaphragm as to control the effective extentof transmitted movement from said diaphragm to said device due totemperature changes, said super'estructure having a coemcient ofexpansion different from that of said diaphragm.

5. A heat compensating, diaphragm controlled operating unit for a deviceoperated by fluid pressure comprising a casing, a diaphragm disposedWithin lthecasing and secured around its periph-- ery in airtightengagement with said casing, supporting means on said casing designed tosupport mechanism for operative connection with the diaphragm, saidcasing being formed from a metal having a higher coeilicient ofexpansion ythan the diaphragm and of an area and thickness to causeexpansion and contraction of greatest degree inrdirections radially ofits center in re-v sponse to heat conditions encountered, said diaphragmbeing so formed as to expand and contract to its greatest degreesubstantially at right angles to its principal plane in response to heatconditions encountered, whereby said fcasing causes linear expansion andcontraction of said diaphragm in responsey to heat conditions, saidsupporting means on the casing possessing such thermal properties as toexpand and contract to its greatest degree in a predetermined directionresponsive to heat conditions, and being of a metal having apredetermined coeflcient of ex- -pansion, the properties of thermalexpansibility and contractibility of the casingl and supporting meansbeing predeterminedly correlated to those of the diaphragm as to controlthe eiective extent of transmitted movement from said diaphragm to saiddevice due to temperature changes.

6. A heat compensating, diaphragm controlled operating unit for a fluidpressure operated device, comprising a diaphragm having predeter- `minedproperties of thermal expansibility and contractibility, and thermalresponsive support- 'ing means for said device in spaced position aroundsaid movement transmitting means and operatively connected to saiddiaphragm and having properties of thermal expansibility andcontractibility predeterminedly correlated to those of said diaphragm asto control the eiective extent of transmitted movement from saiddiaphragm -to said device due to temperature changes.

RiFAT -AVIGDORQ

